Rotary engine



Sept. 30, 1930. E. WILDHABER 1,777,023

ROTARY ENGINE HG1 V 52,56

Filed AApril 6, 1927 2 sheets-sheer 1 r- 5f eillriuiruls.'

, J 65 es Y TYP( f 6 )VT/XK l 18 i] l. 4+ 2z l sept. 3o, V193:0. E,wlLDHABER 1,777,023

ROTARY ENGINE Filed April 6, E192? sheets-sheet 2 FIG@ . INVENTORPatented Sept. 30, 1930 fren-ESTATES *PATENT :oFFeicE ROTARY ENGINE JApiiication mea Api-ii e; ifea?. seriai 'Na iaiss.

a Thelpreseiit invention `relates to rotary enl igines, and especiallyto turbines using a compressible medium, suoli as `for instance steamorcombustion gases. Y vOne purpose of the present invention is to deviseaiiio'vel and eiiicient arrangement of `geared turbines. lAnother objectis to provide a turbine having a plurality of rotors mounted onparallelaXes and-containing a `minimum internal resistance. A further"objectais to provide afturbinehaving a plurality of rotors mounted onparallel axes and provided with velocity stages, iii-which no stationaryblades are provided intermediate ls-the movabley blades. VVelocitystages, :some-` times calledf'Curtis Istages, areknown to contama'plurality `ot ringsof` blades movable in unison with each other andutilizing the lziiietic 'energy of the inediumwhile main- 1 `taining thepressure oi the medium the same beforeand after itpasses'through said`plul Qrality of ringsofblades. In standard practice, stationary bladesare disposed inter`l` mediate adjacent rings of inovahle blades."I Thesaid stationary-bladesare known to con# sinne much energy and to reducethe e'fiiciency or the velocity stages. An object of thepresent'inveiition is to do away with these latter losses andv to raisethe efficiency of Velocity Hostages to-a much higher level', byproviding movableblades only,"adjacent rows of blades` `moving inopposite directions.

Other ObjeCtsWill be apparent in the speci-' a .ication and fr'oinreciting the appended :i5 claims.v l

` My invention is illustrated by way of exaainples in the'accompanyingdrawings, in

which Figfl isa somewhat simplified plan' view l0 of a ygearedVsteamturbine constructed in accordance `with thez'present invention,with npart ofthe upper cover removed and showing ithe rotors partly in'axial section.

FigJQ is a sectional view'ofthe sa sectioni-beingwtalzen along linesA-A` of "Fig v3l is'a side view of the geared steam 1 turbinetshown inFig. l.

. FigMl-is afschematic plan view of another form'o; steam-'-or `gasturbine constructed rotors, the

according to the piiesentlinvention, with the upper cover removed andlshowing the rotors in axial section.

5 is a diagram"-explaiiiiiigftliel preferred''arrangement when rotorsareprovided.

Fig. G is a diagrammatic plan view, partly more than twoa a section, otanother form of steam turbine 'constructed' according to the present'inveii- "ance "with tlief present invention. a `Fig. 9 is a developedsection through rotary bladesysimilar to vlil-ig. 8,'.sliowing however amodified arrangement.

Fig.V l() and Fig; l1 are velocity diagrams for explaining Ytheinclinations o i' the blades shown: in Fig. 8 and F ig. 9. Fig; lQis apartialsection taleiialong the aXes of a pair of rotors constructedaccording to amodificati on of my invention. Fig. 13 .is a View inaxialdirection oi the rotors shown in Fig. l2, and of intermediatestationary parts, at halt the scale of Fig.` l2. 4In tlieiFigures l, and3, the characters l1 and Yl2 denote. two rotors in the form of drums,which are rotatable onparallel axes 13, 14,'in the same direction ofrevolution, as

indicated by arrows l5, lGin Fig. 2. The

rotors are secured to flanges 18, of the shafts or axes 13, 14, by anysuitable means, such as screw bolts, not' further indicated in thedrawing. The rotors extend in a casing consistingy oitl two parts 2l,22,wvliich may` be tightly bolted together with flanges 2l', 22. Theshafts 13, lll project out oi the casingfV 2l, 22 on either side,andpass stuiiing boxes 24 of known structure, indicatedV by theirgeneral outline. The shafts 13, 14 are journalled in a pairof bearings25, and on one side contain circular grooves 27, engaging a thrustbearing. rlhe casing as well as the bearings rest on a base 30, asoutlined in Fig. 3.

The rotors 11 and 12 contain blades 31, 32 arranged in rings 311, 312,313, 314, 315 and 321, 322, 323, 324, 325 of such diameter that theyoverlap. The overlap is seen especially in Fig. 2. Usually the bladesare pieces separate from the rotor drums and are rigidly secured to themby known means such as slots 33, 34 of dove tail form or other suitableform. The blades themselves as well as the manner of securing them tothe rotors are the same as in usual practice. It is understood that theblades may also be made one'piece with the rotor drums, if so desired.

A medium, such as steam, or combustion gases, is led to the blades at35, which is a point where the rotors overlap. The medium then passesgradually through the blades from the high pressure side 35 to the lowpressure side 36, high pressure side being the side of larger pressure,although the pressure in some cases may not be actually high, forinstance in exhaust turbines constructed according to the presentinvention.

The medium passes first through the stationary nozzles 38, and thenthrough the ring 311 of blades of rotor 11, through the ring 321 ofblades of rotor 12, and continues to pass through the rings 312, 322, 31323, 314, 324, 315, 325, which rings belong alternately to the tworotors.

The medium passes therefore through the rings not on their whole, butonly on part of the circumference, namely on the part, where adjacentrings of the different rotors overlap.

Moreover it is frequently desirable to not fully utilize the whole areaof overlap, but to leave out the corners 40, (Fig. 2) where the twooutside circles 41, 42 intersect. The iiowing medium will then occupy anarea between the dotted lines 43 and between the overlapping circles 41,42.

The flow of the medium can be controlled by various means, such as bysuitably placing the initial nozzles 38, to cover only part of theoverlap if so desired, and by providing a member 44 after a ring ofblades, especially after the last ring of blades 325. Member 44 has anopening or window, which ends along the dotted lines 43 (Fig. 2), andwhich therefore prevents the medium from passing through the extremecorners already referred to.

In addition stationary members 45, 46 (Fig. 2) are provided, whichextend inside of the rectangle formed by the parallel lines 47 and 48,(or which may be made to extend all around the rotor and which occupythe space on the outside of each ring of blades, thereby preventing themedium from iiowing outside of the rings of blades.

Rotary engines constructed according to the present invention belong tothe multiple rotor group already referred to, and form a. novel type ofthis group.

One important advantage of this group lies in the reduced number ofstages required, inasmuch as rotating blades are substituted forstationary blades of the single rotor type, so that energy istransmitted to two rings of blades per stage instead of only to one.

A further important feature lies in the high eiiiciency attainable,inasmuch as the intei-nal friction losses are confined to such bladeswhich transmit energy.

Another prominent feature lies in the fact that the outlet energy can befully utilized. The kinetic energy of the medi um leaving one ring ofrotating blades may be fully recovered in the subsequent ring of blades.This feature permits to further reduce the number of stages, as will befully explained hereafter.

All these advantages are maintained in rotary engines constructedaccording to the present invention. But whereas in the known engines ofthe multiple rotor group these advantages are bought with complicationsin the further design, the further design and the general arrangementare utterly simple in the present case.

It is evident from Fig. 2, that opposite peripheral velocities of theblades result in an equal direction of revolution, as indicated by thearrows 15, 16. The rotors may therefore be provided with pinions 50, 51meshing with the same gear 52. Shaft 53 of gear 52 is shown in the planeconstituted by the two axes 13, 14. Shaft 53 is rotatably held in twobearings 54, and delivers energy on the side 56 in a manner not furtherindicated. Gear and pinions may be provided with herringbone teeth 58,as indicated.

The pinions are integral with their shafts 60, G1 and coaxial with theshafts or axes 13. 14 of the rotors. The pinions are driven from shafts13, 14 by means of clutches G2, (33 ol' known design, indicated merelyas rectangles. Especially in the case of more than two rotors, asoutlined hereafter, the clutches are so designed as to permit engagementand disengagement while the turbine is running.

The exhaust of the turbine is received at 3G, and is led away through anexhaust pipe 65, in the case of steam turbines preferably to acondcnsor.

It is noted that shaft 53 is centrally located with respect to theturbine, whereas even in known single rotor turbines this shaft isOifset. Moreover gear 52 can be made smaller than a gear of the samecapacity in av single rotor turbine, because the load is distributed totwo pinions instead of only to one.

For simplicitys sake I have omitted in the drawings most of those knownparts which go with engines of the kind referred to without furtherexplanation, especially valves, a centrifugal governor, a lubricationsystem.

lus

'i ivano-23 cording to the present "inventiomand 'intend` ed especiallyfor smaller capacities.

The medium, such as steam, is' introduced at 68, and flows inV a general`direction parallel to the axes 7 0, 71 of the rotors 72,173 to the side74 of lower. pressure. The rotors contain each three Irings 75, 76 ofblades,`

which overlap each other. y

` The parallel shafts 70, 71 Vof the two rotors are journalled` inbearings 77, 78, 79, 80,' placed on a 'commonA frame Y81. "The turbinehousing also stands on this frame.` It is again composed of two parts,which in operation are tiohtlT boltedl together and of which the upperpartor coverhas been removed in the drawing. efore leaving 'the casing,the shaftsl 70, 71'pass oneither side through stuffing boxes 83indicated diagrammatically by rectangles. Thestuftin'g boxes aretightly'secured to the casing by' means such as' rings 84, bolted to thecasing and to the stuffing-boxes. l

Intermediate the two bearings 77, 78' and T9, S respectively and onthesideof higher pressure,i pinions, 85 are provided, which Aar'ecoaxial with Aand vfreduently also integral Ywith the shafts 70, 71.'The -pinions 85, 85'

contain helical teeth 86 of such hand, that thel thrust resultingfromthe tooth pressure isin a direction opposite to the thrust exertedon the rotors by the medium. In this manner the thrust bearings 87, 88are called upon tocarry only a reduced load.

The pinions inesh with the same helical gear 90, rigidly secured to ashaft 91 of 'any suitable machine, such as ,for Vinstance an' electricgenerator 92 indicated only withpart of its outline.

It is noted, that the energy isV here 'transmitted on the side of higherpressure, whereas the known turbines transmit the energy on the side hflower pressure'. By providing an arrangement as shown,'the length fof-the unit may be reduced. y, f l

`An arrangement of aturbine withm'ore than two rotors isdiagramm'atically 4outlined in Fig. inV which`93fd-enot'e thec'enterslof six rotors. They arearranged at equal "diss tances from a'centralaxis 94, and contain pinions 95 meshing with the same gear 96 rotatableon axis 94. The 'pinions receive Vthe drive 4from ytheir rotors throughclutches, such as indicated at 62; 63 inA Fig. l.. A fmultiple rotorarrangement asindicated permits a high 4eiiiciencyfwithin a very greatrange of loads. At small loads the inlet of a number of rotors is shutofl, the clutches of said rotors are. disengaged, and these rotors arestopped. They cease therefore to consumer energy through internalfriction. I

A further vnovel application isillustrated in F ig. 6. IThe turbineoutlined in F ig. 6 is a coinbinationfof the new type just describedwith a known type. Two rotors 100, 101 aref rotatable on parallel axesY102, 103 inthe saine direction of revolution. They contain: onthe highpressure side blades arranged in rings of such diameter, that theyoverlap, as de- 'scribedwith "reference toltigs. l-ft. They'- alsocontain. blades arranged inlrings of a diameter smaller than thedistances ofthe two axes 102, 103,0f known design, be it of the actiontype or of the reaction type.

The medium of such as steam, is intro* duced at a point 104 wheretherings of blades overlap. Itv passes first through stationary nozzles105, and then alternately through rings of blades of thel two rotors,namely through rings 1061, 1071,' 1062, 1072, 1063, 1073.`

i So far the flow of medium'occupies only part of the circumferenceofthe ringsofblades, namely the area ofoverlap, or part ofL such area.`After having passed throughtheoverlapping rings, the medium passesthrough rotor in a known manner,` and preferablyon `the wholecircumference. 1t passes through stationary blades or channels108,`andthen alternately through rotating blades 'and stationary blades110. l

The casing infront may be made offaln upn per and a lower part, thetwo"roto1s"`being covered by the same casing 111.1K In therearpreferablysepa'rate casings 112, 113'ar`e used on the two rotors. Beforeleaving' the easing, l

the shafts 102, 103` pass through stuffing boxes 1141; The shaftsaresup'ported on bearings 115. The reduction gears are'oniitted in thisfigure.

Fig. 7 is a view of the rotors shown in Fig.

6 and the stationary parts 117, 118, whieh prevent theniedium freinflowing outside of the blades. The initial nozzles 105 are indicated indotted lines. Every"ring 'of blades, in which a pressure drog takesplace."

may be secured to aseparate dis {,so that the stationary members 117,118, intermediate the disks, extend inwardly as far as thehubs 119,

of said disks.

ergy of the expanded steam is in known pracl tice freruiently utilizedin so-called Curtis stages, that is to say the high velocity of thesteam is not completely used up ina single ring of rotating blades, butin a plurality ofl rings, stationary blades for reversing 'the'Separate` disks may be used especially, when the drop 1n pressure issteam being placed between two subsequent rotating rings. In this knowncase the pressure of the steam is the same innnediately before enteringthe lirst and alter leaving the last ring oi a plurality of rotatingrings oi blades.

Turbines constructed according to the present invention can utilize asimilar rangement with Jarticular advantage. because they eliminate itsmain drawback oit low eliiciency. I therefore preferably use on the highpressure side two or more or" such stages, so that the pressure ot themedium is substantially the same betere and atter two or more subsequentrings of blades; such as before ring 106l and after ring 1071 (Fig. 6),or before ring` 106l and alter ring 108:.

I may use this type of stage-s excl .sively on the high pressure side,where the difierent rings of blades overlap, or l may combine suchstages with stages of the reaction type.

Such a combination olf stages is indicated in Fig. 8, another in Fig. 9,and Fia'. 1() and Fig. 11 are explanatory velocity diagrams.

122 denotes stationary channels or nozzles having a minimum area 123intermediate th; ends 124i, 125. They will therefore pei lit the mediumto assume a velocity, at end 125, in excess of the velocity of sound, aswell known. In Fig. 10, the velocities are plotted as straight lines,whose linear distances are proportional to tho velocities and whosedirections are parallel to the direction of' the velocities. Absolutevelocities are drawn in full lines, and relative velocities of theinedium with respect to the rotating blades are shown in dotted lines.

After having passed through and expanded in the nozzles 122, the mediinnassumes a velocity such as 126 (Fig. 10). 'l`he velocity 12T of themedium relatively to the rotating blades 128 may then be determined byplotting the peripheral velocity 12) ot blades 128 in Fig. 10, asindicated and completing the triangle 128, 127, 128. Prel'crably theblades 128 have the same inclina ion on the entering side as relativevelocity 12T, as known. rlhe medium leaves the blades 128 with an equal.but oppositely directed rch'.- tive velocity, indicated at 180 in Fig.10, no relative acceleration taking place in the rotating blades 128.rllhe absolute velocity 132 of the medium. alter leaving blades 128, maybe determined by plotting the peripheral velocity at 129. and bycompleting triangle 130, 182, 129. rIhe medium now enters the blades 183rotating' in opposite direction.

The relative velocity 13a may be determined as before, see Fig. 10. Ylherelative velocity 134 of the medium, when leaving thel blades 188 isequal to but oppositely directed as compared with the relative velocity1811 when entering. Neither in the blades 128, nor in the blades 183does the medium experience an acceleration rolatively to the blades. Thepressure oi the medium when entering blades 128 and when leaving blades133 is theretore the same. The absolute velocity has changed from anamount 126 to an amount 135, the latter beingdetermined in the mannerexplained.

In the example indicated in Fig. 8, I have shown rotating blades 13G,137, 138, 139, of dillierent type disposed after the blades 128, 183. Inthese blades the medium assumes a larger relative velocity when leavingthe blades than when entering. fr drop in the pressure of the mediumtherefore takes place in the rotating blades. Blades et this type havefrequently been called reaction blades. lVhen it is desired to have aparticularly small number ol stages. I may prnvide blades 138,187,188which 'form channels having a minimum area 14:0 intermediate the twoends. so that the medium may assume a velocity oeyond the velocity ofsound. A velocity diagram corresponding to such blades as 186, 137, 138is shown in Fig. 1l.

rllhe absolute velocity' oi"A the medium when entering blades 18h, isdenoted by character 1451. The relative velocity 14:2 may be dcterminedin the same manner as explained before. lfhe relative velocity 1li-3 otthe medium when leaving lades 13G may be determined in known manner fromthe area ot the channels and from the changed density or speciiicg'avity oit the medium. The absolute velocity is then les. Equal orimilar' velocities may be provided in the blades 137, 138. The lastrinfr of blades is preferably so designed, that the absolute velocitv otthe medium, on the leaving side, is a minimum and directed substantiallyparallel to the axes ot rotation.

rllhe kinetic energy of the medium which corresponds to the saidabsolute. Velocity namely lost, whereas the kinetic energy nl themedium, which corresponds to an absolute velocity 1414-, may berecovered in the subsequent ring oi blades. ln all rings ol blades butthe last one, large leaving veio-.- ities may therefore be provided,which icature permits to `further reduce the number ol' stages ascompared with the single rotor type of turbines. i'

In Fig. 9 blades are shown arranged in a larger number of rings orstages as conipared with Fig. 8. rl`he blades 145. 146. 1l?. 148, 149are inclined in their general direction 150 to the direction 152 otperiphera motion, as are the blades 13G-139, but they do not contain aminimum area intermediate their ends. In other words they are designedfor relative velocities ot the medium not in excess of the velocity ofsound.

rlhe Figs. 12 and 13 diagrammatically illustrate an embodiment ot thepresent invention', in which the flow of the medium extends in axialdirection only on the whole, and extends radially in the individual.stages. It

flows outwardly in the individual stages, as 1s usual'm centrifugalpumps. The mediumA Vflows inside of the area constituted by the Circles158, 159 and the lines 160, 161. After moving `outwardly in one rotor,it passes to a pointnear the hub of the other rotor, and then againstarts to move outwardly on said rotor. The arrangement of the variousstages of the rotors is evident from Fig. 12, which is a section in alarger scale, through the two axes of the rotors. The medium passesalternately from a stage of one rotor to the subsequent stage of theother. The rotating blades 154 are secured to or part of bodies 155,which are'rotatable either on axis 156, or on axis 157. Y f

It is understood that such changes and further modifications maybe madein my in vention,as fall within the limits of the appended claims.

What Ielaim is: y

l. In a geared turbine using a compressible medium, a rotor, bladesprovided on said rotor adjacent its periphery, two bearings forrotatably holding said rotor, means for guiding said medium through saidblades from a side of higher pressure to a side of lower pressure, apinion forming part of said rotor and disposed between said two bearingson the side of higher pressure, agear meshing with said pinion, andstufling boxes disposed adj aeent said rotor, one of said stuliiingboxes being disposed between said pinionand said blades. v

2. A geared turbine usingva oompressible medium, having two rotorsrotatable Yon parallel axes, said rotors containing bladesl arranged ina plurality of rings oit' such diameter that they overlap, each rotorbeing disposed between two bearings,mearnsfor guiding a medium to saidblades at a point where they overlap, a pinion arranged coaxially witheach rotor between said two bearings, a

stuliing box disposed between said pinion and said blades, and a gearmeshing. with both'ol said two pinions. j

8. In a geared turbine using a oompressible medium, a rotor, bladesprovided onsaid rotor adjacent its periphery, two bearings for rotatablyholding said rotor, means for guiding said medium through said bladesfrom a side of higher pressure to a side of i lower pressure, a pinionforming part of said rotor and disposed between said two bearings, agear meshing with said pinion, and f stuiing boxes disposed adjacentsaid rotor, one of said stuffing boxes being disposed between saidpinion and said blades.

Il. In a turbine using incompressible medium, two rotors rotatable onparallel axes, said rotors containing blades arranged in rings of suchdiameter that they overlap, stationary nozzles disposed adjacent a pointof overlap for converting pressure energy of the medium `medium theVVsame before and after it passes through all the last named rings ofsaid two rotors.

ERNEST VILDHABER.

